Even when the social order appears intractable, social change is constantly unfolding all around us, finding expression in the accumulation of small acts of resistance as much as in dramatic moments of revolution. Psychologists should take interest in the dynamics of social change, whether mundane or dramatic, for at least two reasons. First, the explanation of when and why change occurs -or fails to occurrequires analysis of ordinary people's thoughts, feelings, and behaviors. To understand fully the conditions under which people act in ways that support or challenge the status quo, we simply cannot afford to overlook the role of psychological factors. Second and related, processes of social change invite us to (re)appraise the moral and political implications of psychological knowledge. How do we reduce discrimination against others? When do we recognize and challenge social inequality and when do we accept or even endorse it? How can we create more inclusive forms of identity and community? Such questions elide the traditional division between scholarship and advocacy. They require us to demonstrate how psychological knowledge helps create a more just and tolerant society. Perhaps less comfortably, they require us to recognize how our discipline may be complicit in maintaining social inequalities.In this chapter, we discuss two psychological models of social change, namely prejudice reduction and collective action. Both models focus on the problem of "-improving relations between groups to reduce social inequality and discrimination. However, they propose different psychological pathways to the achievement of this goal and prioritize different core questions. As we shall see, the prejudice reduction model primarily addresses the question "How can we get individuals to like one another more?" whereas the collective action model primarily addresses the question "How can we get individuals to mobilize together to challenge inequality?"The first section of the chapter elaborates the fundamental principles and underlying assumptions of these models. The second section explores the relationship between the two models of change, focusing on the allegation that prejudice reduction exerts counterproductive effects on collective action. The chapter's 481